Temporary toilet

ABSTRACT

A compact and easily transportable temporary flush toilet can be installed where the toilet cannot be connected to a water supply system and no frequent maintenance is possible. The temporary toilet includes a toilet bowl, a flush water tank for storing flush water used to flush the toilet bowl, a sewage tank for storing sewage from the toilet bowl, a water vapor separator for separating water from gas containing water vapor vaporized from sewage in the sewage tank, an exhaust pipe through which gas is guided from the top of the sewage tank to the water vapor separator, and a distilled water pipe through which water separated from the gas in the water vapor separator is supplied to the flush water tank. Thus, storage of the sewage, microbial decomposition of waste, and evaporation of the sewage take place in the sewage tank alone.

TECHNICAL FIELD

The present invention relates to a flush toilet which can becontinuously used without supplying additional water from outside.

BACKGROUND ART

Toilets are essential in order to maintain hygiene of an environmentwhere humans live. In order to maintain high standards of living wherethe population density is high, flush toilets are indispensable, insteadof toilets of the type which are eventually simply dumped into theenvironment. But in rural communities which are far from cities andcannot afford to construct a sewage system, toilets are often usedhaving a sewage treatment tank in which waste is decomposed utilizingmicroorganisms. It is also being considered to use sewage as flush waterfor flush toilets so that flush toilets can be installed in areas whereit is difficult to construct a water supply system.

For example, Patent document 1 discloses a heating/evaporation typetoilet system including a flow type waste tank in which waste from atoilet bowl is crashed, an evaporation oven in which the crashed wasteis evaporated, two deodorizing pipes for deodorizing water vapor fromthe evaporation oven, and a filtering tank in which water is recoveredfrom the water vapor in the flow type waste tank, wherein a large amountof waste is circulated to soften it. In the evaporation oven, the wasteis heated until it disappears. That is, by crashing waste in the wastetank and then heating it in the evaporation oven, nothing remains in theoven (see paragraph [0015] of Patent document 1). Since water vapor isdeodorized in multiple stages, foul odor is substantially reduced.

Patent document 2 discloses a circulation type flush toilet systemincluding a biological decomposition tank in which waste is biologicallydecomposed, a filtering tank in which the biologically decomposed wateris separated into solid and liquid components, and a decoloring tank inwhich the water separated in the filtering tank is decolored, whereinthe water decolored in the decoloring tank is used as flush water, whilewater overflowing the decoloring tank is returned to the biologicaldecomposition tank. This toilet system further includes an evaporationtank in which a portion of the filtered water is evaporated. The watervapor thus produced is condensed back into water and returned to thebiological decomposition tank (FIGS. 1 and 2 of Patent document 2).Blowers are connected to the filtering tank, biological decompositiontank and evaporation tank, respectively, to supply compressed air intothese respective tanks (see e.g. [0020] of Patent document 2). Anelectric power pump is used to draw water from the biologicaldecomposition tank into the filtering tank. The pump is controlled byupper and lower float switches so that the water level can be finelyadjusted (see paragraphs [0021] to [0024] of Patent document 2). Thissystem is a large-scale system which can be used not only as a toiletbut also as an industrial sewage treatment system (see paragraph [0064]of Patent document 2).

Patent document 3 discloses a temporary toilet unit including a urinaland a toilet bowl. If this toilet unit is used in a civil engineeringsite, the toilet bowl is almost exclusively used for defecation and thusis less frequently used than the urinal. Thus, by biologicallydecomposing the waste from the toilet bowl, it is not necessary to emptythe tank storing the waste from the toilet bowl for a prolonged periodof time (see paragraph [0010] of Patent document 3). On the other hand,sewage from the urinal is aerated in an aeration tank and thenevaporated by heating with a heating device so that a very small amountof solid content remains. This makes it possible to extend the intervalsbetween maintenances of this toilet unit to about one year (paragraph[0009] of Patent document 3).

PRIOR ART DOCUMENTS Patent Documents

-   Patent document 1: JP Patent Application 2001-336195A-   Patent document 2: JP Patent Application 2005-131536A-   Patent document 3: JP Patent Application 2006-328786A

SUMMARY OF THE INVENTION Object of the Invention

While the toilet system disclosed in either of Patent documents 1 and 2can sufficiently deodorize and decolor waste produced, it is large insize. Washing and replacement are considered necessary for thedeodorizing pipes and the filtering tank of Patent document 1. Thisshortens the intervals between maintenances. The toilet system of Patentdocument 2 also requires a plurality of treatment tanks, in which therespective water levels have to be adjusted. Thus, the treatmentmechanism of this toilet system, including treatment tanks, isinevitably larger in size than the toilet body itself. There are a largenumber of component parts that need periodical maintenance. It istherefore troublesome and time-consuming both to install this toiletsystem and to maintain it. For these reasons, neither of these toiletsystems can be installed in areas where once the toilet system isinstalled, it has to be left unattended for a long period time, such ason riverbeds, campsites, mountain trails, etc. These toilet systems aretherefore cannot be practically used as temporary toilets in view of thedifficulty in storage, transportation and operation. These toiletsystems may be used in civil engineering sites, because there is heavytraffic of people in civil engineering sites. But even in such places,because the above toilet systems are heavy and large in size, locationswhere they can be installed are limited.

The temporary toilet of Patent document 3 can achieve its expectedadvantage only if it is used mostly by men. If a large number of womenuse this toilet, the waste from the toilet bowl dramatically increases,thus shortening the intervals between maintenances. Since sewage issimply evaporated and not reused as flush water, flush water has to besupplied from outside. Thus, this toilet cannot be installed where itcannot be connected to a water supply system.

An object of the present invention is to provide a temporary flushtoilet which is compact in size and thus is easily transportable, andwhich can be installed where the toilet cannot be connected to a watersupply system and no frequent maintenance is possible.

Means to Achieve the Object

In order to achieve the object, the present invention provides atemporary toilet comprising a toilet bowl, a flush water tank whichkeeps flush water to be supplied into the toilet bowl, a sewage tankwhich keeps sewage discharged from the toilet bowl and decomposes thesewage by microorganisms, a water vapor separator capable of separatingwater from a gas containing water vapor which has been evaporated in thesewage tank, an exhaust pipe through which the gas is guided from a topof the sewage tank to the water vapor separator, and a water supply pipethrough which the water separated in the water vapor separator issupplied into the flush water tank.

Only up to about 80% of flush water used to flush the toilet bowl can beevaporated and reused as flush water, and the remaining water isdischarged into the atmosphere in the form of water vapor. Thus, if onlyflush water were evaporated and recycled, the total amount of waterstored in various parts of the toilet according to the present inventionwould decrease gradually. But according to the present invention, sincesewage containing not only flush water used to flush the toilet bowl butalso human waste, which contains a large amount of water, is evaporatedand reused, the total amount of water stored in the various parts of thetoilet according to the present invention can be maintained at the samelevel, without the need to receive water from outside such as from apublic water supply system or from a water supply tank car. This is themost important feature of the present invention.

Another important feature of the present invention is that sewage storedin the sewage tank is biologically decomposed in the sewage tank andalso evaporated in the sewage tank. Thus, the sewage tank also serves asa biological decomposition tank and a water vaporization tank. Since thesewage tank according to the present invention serves theabove-mentioned triple purposes, the toilet according to the presentinvention is simpler in structure, less likely to malfunction, andsmaller in size, than the devices disclosed in Patent documents 1 and 2.For smoother and quicker biological decomposition of sewage, theinterior of the sewage tank is preferably kept at 25° C. or over. Aslong as enough water is stored in the sewage tank, a sufficient amountof water can be evaporated without the need to heat sewage in a separateoven or furnace. Since the sewage tank can keep a sufficient amount ofwater, it is possible to maintain the total amount of water kept in theentire toilet at a sufficient level.

Microbial decomposition itself produces heat. But a heater may be addedto further heat the sewage tank. Further, means may be provided forsupplying gas for aeration into the bottom portion of the sewage tank toaccelerate decomposition by aerobic bacteria and to agitate sewage,thereby preventing formation of masses in sewage.

When human waste is decomposed by microorganisms at a temperature rangeof 25 to 30° C., particularly at a temperature range of 28 to 30° C.,odor will not be particularly strong. Gas containing water vaporevaporated from the sewage in the sewage tank is trapped in the watervapor separator to separate water from the gas, and the gas deprived ofwater is released into the atmosphere. Thus, the toilet according to thepresent invention produces far less odor than the temporary toiletdisclosed in Patent document 3, in which water vapor from sewage isdirectly released into the atmosphere. Since temporary toilets,including the one according to the present invention, are installed atplaces where humans do not live on a permanent basis, slight odor fromthe temporary toilet according to the present invention will hardly stayor accumulate to such an extent as to offend people around the toilet,but will easily diffuse even by light winds.

In order to provide electricity for the water vapor separator, pump forflushing the toilet, heater, aerator, etc., the temporary toiletaccording to the present invention may further includes solar cells anda battery for storing the electricity generated by the solar cells. Withthis arrangement, it is not necessary to connect the toilet according tothe present invention even to the public electricity network, whichmakes it possible to use the toilet as a completely stand-alone toiletunit.

Advantages of the Invention

The temporary flush toilet according to the present invention can beinstalled at any location where there is neither a water supply systemnor a sewage system, because the toilet according to the invention canbe used for an indefinite period of time without the need for anywillful supply of water from outside. Once installed, this toilet isvirtually maintenance-free. But if it is desirable or necessary, watersuch as rainwater may be supplied from outside, for example, if a largeamount of flush water is consumed during a short period of time.

Specifically, the toilet according to the present invention can beinstalled on riverbeds, in campsites, along mountain trails, in or bybeach houses, and in other places where there are usually no watersupply system and no sewage system. The toilet according to the presentinvention can also be installed in civil engineering or constructionsites or any other places where conventional temporary toilets areusually installed. When installing the toilet according to the presentinvention in one of these places, and when removing it, it is notnecessary to connect and disconnect the toilet to and from a watersupply system or a sewage system. Thus the toilet according to theinvention can be easily installed, removed and/or relocated to anotherplace.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the outer appearance of a temporary toilet according to thefirst embodiment of the present invention.

FIG. 2 is a schematic vertical sectional view of the temporary toilet ofthe first embodiment;

FIG. 3 is a horizontal sectional view of a portion of the temporarytoilet of the first embodiment, including its tank.

FIG. 4 shows the flow of water in the temporary toilet of the firstembodiment.

FIG. 5 is a top plan view of a toilet bowl of the temporary toilet ofthe first embodiment.

FIG. 6 is a wiring diagram of the temporary toilet of the firstembodiment.

FIG. 7 is a schematic vertical sectional view of a temporary toilet of asecond embodiment.

FIG. 8 is a horizontal sectional view of the temporary toilet of thesecond embodiment.

FIG. 9 shows the flow of water in the temporary toilet of the secondembodiment.

FIG. 10 schematically shows an embodiment having a rainwater storagetank.

BEST MODE FOR EMBODYING THE INVENTION

Now the embodiments are described in detail.

First, the temporary toilet of the first embodiment is described withreference to FIGS. 1 to 6.

FIG. 1 shows the outer appearance of a toilet unit 100 of the temporarytoilet of the first embodiment. The toilet unit includes a toilet booth101 which can be occupied by a user, a separate control booth 102 whichhouses e.g. a control device, and a base 103 having a front end portionprotruding from the front end of the toilet booth 101. Users can use thefront end of the base 103 as a step when accessing the toilet booth 101.Standing on the step of the base 103, a user can open the door 105. Atoilet bowl body 104 including a flush water tank 11 is mounted on thefloor of the toilet booth 101 with a predetermined space left betweenthe toilet bowl body 104 and the door 105.

FIG. 2 is a vertical sectional view of the toilet unit 100 of thetemporary toilet of the first embodiment. FIG. 3 is its partiallyschematic horizontal sectional view. FIG. 4 shows the relationshipbetween the flow of water and various structural elements. Referring toFIG. 4, the flow of water is now described.

The flush water tank 11 is mounted in the toilet bowl body 104. Flushwater used to flush the toilet bowl 18 after use is stored in the flushwater tank 11. A foot pump chamber 12 is provided in the toilet bowlbody 104 at its front right corner so as to be completely isolated fromthe flush water tank 11. A foot pump 13 is mounted in the foot pumpchamber 12. A foot pedal switch 14 protrudes from the front side of thetoilet bowl body 104. When the foot pedal switch 14 is depressed, thefoot pump 13 is activated to suck flush water through a pump suctionpipe 15 extending from the foot pump chamber 12 into the flush watertank 11, and then feed the thus sucked flush water into a pump feed pipe16. The flush water in the pump feed pipe 16 is injected into the toiletbowl 18 through a nozzle 17. The injection angle of the nozzle 17 isadjusted such that the injected water circulates around the surface ofthe bowl 18 before dropping into the hole of the bowl 18 so that theentire bowl 18 can be washed with a minimum amount of water. FIG. 5,which is a top plan view of the toilet bowl body 104, shows the detailsof this arrangement.

When the foot pedal switch 14 is depressed and flush water is injected,a bottom lid 21 provided at the bottom of the toilet bowl 18 also opens.Thus, the flush water used to wash the toilet bowl 18 drops into a wastestorage tank 22, together with waste. The waste storage tank 22 ispartitioned from the flush water tank 11. The letter A in FIG. 2indicate sewage dropped from the toilet bowl 18. Once the sewage dropsinto the tank 22, the lid 21 closes, preventing the odor of the waste inthe tank 22 from rising into the toilet bowl. Sewage A in the tank 22drops into a sewage tank 24 in the base 103 through a sewage dischargepipe 23. Thus, sewage A scarcely remains in the waste storage tank 22.

Sewage B, which is organic, in the sewage tank 24 is decomposed bymicroorganisms, while its water content gradually evaporates. Aircontaining water vapor C produced in the tank 24 is supplied through anupwardly extending air exhaust pipe 31 into an air pressurizing pump 32in the control booth 102, where the air pressurizing pump 32 pressurizesthe air containing water vapor C to reduce the amount of saturated watervapor, thereby allowing the water vapor C in the air to be condensedinto water. The water is separated in a water vapor separator 33 andthen supplied back into the flush water tank 11 through a distilledwater pipe 34 so that the water is reused as flush water D.

Dry exhaust air E which has been separated from the water vapor C andthus is low in water content is discharged to outside through adischarge tube 35 by means of an exhaust fan 36 provided at an upperportion of the toilet unit 100.

The water vapor separator 33 may be an ordinary dehumidifier, a coolingair compressor, or a dry separator of the cyclone type. Alternatively,the water vapor separator may be of the type which contains porousparticles of e.g. silica gel which can adsorb water and includes meansfor releasing the adsorbed water by heating. But the separator 33 may beof any other type which can separate water from air and take out thethus separated water. In view of the object of the present invention,however, a water vapor separator is preferably selected which issufficiently compact in size and consumes less electricity.

Most part of water held by this temporary toilet exists in the sewagetank 24. The sewage tank 24 occupies substantially the entire interiorof the base 103 to ensure a sufficiently large contact surface area ofwater and air. With this arrangement, water in the sewage tank 24evaporates naturally to a certain extent, without the need to heat thetank 24 to such an extent as to cause excessive evaporation. Also,because the tank 24 is large in volume, microbial decomposition occursin a large volume of water in the tank 24. The sewage tank 24 thusserves the triple purposes as a microbial decomposition tank,evaporation tank, and water storage tank. This makes it possible tominimize the volume of the entire temporary toilet.

Most temporary toilets are mainly used only during the daytime or onlyduring the nighttime. Thus, water accumulated in the sewage tank 24during the busy hours is evaporated, separated from air, and returned tothe flush water tank 11 during the less busy hours. The water thusreturned to the tank 11 can be used during the next busy hours.

The sewage tank 24 includes a mechanism which accelerates microbialdecomposition of organic matter. This mechanism is described withreference to FIG. 6.

This mechanism includes a blower pump 41 in the control booth 102, and ablower diffuser tube 42 extending from the blower pump 41 and uniformlycovering the entire bottom surface of the sewage tank 24. Aerating airis supplied from the blower pump 41 into the blower diffuser tube 42 andis discharged through a large number of discharge holes formed in theunderside of the tube 42, thus agitating, while aerating, the sewage Bin the tank 24 from below. Thus, aerating air supplies oxygen intosewage B, prevents organic solid substances from remaining on the bottomof the tank 24, and crashes organic solid substances into small pieces,thereby accelerating decomposition of organic solid substances.

A branched heater 43 is further provided in the sewage tank 24 which issubmerged in sewage B and capable of uniformly heating the sewage B. Byheating the sewage with the heater 43, organic substances can bedecomposed at a practically acceptable speed even during the wintertime,when the ambient temperature is low and thus microorganisms tend to beinactive. In order to keep the heat produced by the heater 43 in thetank 24, its inner surface is covered with a heat insulating material44, or such a heat insulating material 44 is embedded in the wall of thetank 24.

However, excessive heating of the sewage B may slow down, rather thanaccelerate, microbial decomposition, and also may cause excessiveevaporation of sewage B exceeding the capacity of the water vaporseparator 33. Thus, an electronic control unit 51 is used to optimallycontrol the heater 43 according to various conditions. In particular,the control unit 51 includes a temperature regulator 52 which receivestemperature information of sewage B from a temperature sensor 53 whichis at least partially submerged in sewage B and which adjusts the outputof the heater 43 based on the temperature information from thetemperature sensor 53. Preferably, the temperature regulator 52 isconfigured to stop heating by the heater 43 when the temperature of thesewage B as measured by the temperature sensor 53 reaches or exceeds anupper threshold, which is set at a temperature between 25 and 30° C.,and to restart heating when the temperature of the sewage drops below alower threshold. With this arrangement, microbial decomposition oforganic substances takes place in the tank 24 at a substantiallyconstant rate throughout the year, so that the temporary toilet of theinvention can be operated in a stable manner. Most preferably, thetemperature of the sewage B is kept at 28 to 30° C. because at thistemperature range, microbial decomposition is most active and odor islow.

The control unit 51 controls the output of the blower pump 41 too.Aeration may be carried out continuously or intermittently. If enoughelectric power is available, continuous aeration may be elected becausecontinuous aeration more effectively prevents accumulation of organicsolid substances on the bottom of the sewage tank 24, and allows stablesupply of oxygen to microorganisms. If, on the other hand, savingelectric energy is more important, aeration may be intermittentlyrepeated each for the duration of several minutes, with the intervals ofseveral minutes.

A floating water level sensor 61 is provided in the sewage tank 24,which is connected to a use prohibition display 62 through a switch. Theuse prohibition display 62 is attached to a portion of the door 105where a person who tries to open the door 105 can never miss. When thelevel of the sewage B in the tank 24 rises to a predetermined point,which is typically the upper limit of the capacity of the tank 24,together with the floating water level sensor 61, the switch is adaptedto be closed or opened, thereby changing the indication on the display62 such that the display 62 now indicates that the toilet cannot be used(e.g. by distinguishing the sign “USABLE”, changing the sign “USABLE” to“UNUSABLE”, or turning off a green light and turning on a red light.

Behind the sewage tank 24, an overflow drain 64 is provided which allowsoverflow of sewage B if the toilet is used after the level of the sewageB has exceeded the upper limit of the capacity of the tank 24 and theindication on the display 62 has changed such that it indicates that thetoilet is not usable.

If the level of the sewage in the tank 24, as detected by the floatingwater level sensor 61, falls below a predetermined lower limit, thecontrol unit 51 is configured to turn off the heater 43, airpressurizing pump 32 and water vapor separator 33 to prevent any furtherreduction in water content in the tank 24 by stopping evaporation andescape of water vapor.

An air intake port 63 is formed in the floor of the toilet booth 101,which is located over the sewage tank 24. When air in the sewage tank 24is sucked by the air pressuring pump 32, outer air can be introducedinto the tank 24 through the air intake port 63. The air intake port 63is sized such that no odor in the sewage tank 24 rises into the toiletbooth 101 through the air intake port 63 while a negative pressure isbeing produced in the tank 24 by the air pressurizing pump 32.

Electric power may be supplied to this temporary toilet through electricwires as shown, or may be entirely from a separate solar cell panel (notshown). If a solar cell panel is used, it is necessary to additionallyprovide a secondary battery (not shown) such as a lead battery so thatthe blower pump 41, the heater 43, etc can be kept in operation on rainydays and during the nighttime. If a secondary battery is used, thecontrol unit 51 may be programmed to compare the electric power storedin the battery with the power consumed by heater 43 and the blower pump41 and to stop the aeration by the blower pump 41 if it is determinedthat the electric power stored in the battery is insufficient comparedto the power consumption.

FIGS. 7 to 9 show the second embodiment. FIG. 7 is a schematic verticalsectional view of the temporary toilet of the second embodiment. FIG. 8is a schematic horizontal sectional view of a portion of the temporarytoilet of the second embodiment including a toilet bowl body 104′. FIG.9 shows the flow of water through the temporary toilet of the temporarytoilet of the second embodiment. In this embodiment, the sewage tank 24,which is provided in the base 103 of the toilet unit 100 in the firstembodiment, is housed in an expanded control booth 102. The tank 24 ofthis embodiment can thus have a larger capacity and thus a largerthroughput than the tank 24 of the first embodiment. Even though thetank 24 of this embodiment is large in size, the entire toilet of thisembodiment is still sufficiently compact in size compared toconventional such toilets, which include three separate tanks, i.e. anevaporate tank, a microbial decomposition tank and a storage tank.

The second embodiment differs from the first embodiment in the followingpoints too. First, since the sewage tank 24 is not located under thetoilet bowl 18, and thus its inlet port is located at a point higherthan the toilet bowl 18, a waste feed pump 73 is provided to pump up thewaste in the bowl 18 to the inlet port of the tank 24. The pump 73 isdirectly connected to the center hole 74 of the toilet bowl 18. Inparticular, this pump 73 is provided instead of the waste storage tank22 of the first embodiment at the same location where there is the wastestorage tank 22 in the first embodiment. This pump 73 is preferably apower pump because it is considered difficult to pump up waste in thetoilet bowl to a higher point with a manual pump.

The power waste feed pump 73 is activated, not all the time, but onlywhen flushing the toilet bowl 18. Flush water in a flush water tank 11is supplied into the toilet bowl 18 through a pump suction pipe 15 by awater suction pump 72 which is also a power pump.

The water suction pump 72 and the waste feed pump 73 are activated bydepressing a switch button 71 provided in the toilet booth 101. Inparticular, when a user depresses the switch button 71 after use, thewater suction pump 72 is first activated to inject flush water into thetoilet bowl 18 through the nozzle 17, thus dropping any waste remainingin the toilet bowl 18 into its center hole. Simultaneously when thebutton 71 is depressed, or several second after the button 71 isdepressed, the waste feed pump 73 is activated to pump up sewage droppedfrom the toilet bowl through a sewage discharge pipe 23 under pressureuntil it is fed into the sewage tank 24. The control unit 51 ispreferably programmed to also control the pumps 72 and 73 in the abovemanner, to eliminate the need for an extra control unit.

Since the sewage tank 24 of the second embodiment is larger in size thanthe tank 24 of the first embodiment, and thus the surface area of thewater in the tank 24 is larger, air supplied to the water vaporseparator 33 of the second embodiment contains a larger amount of watervapor in order to more effectively and sufficiently condense such alarge amount of water vapor into water, it is necessary to produce ashigh a pressure as possible in the water vapor separator 33. For thispurpose, in the second embodiment, a compressor 75 is connected to thewater vapor separator 33.

Some of the elements used in the second embodiment only may be used inthe first embodiment too. For example, the compressor 75 may be used inthe first embodiment too. Also, the water suction pump 72 and the switchbutton 71 for activating the pump 72 may be used in the firstembodiment. In this case, the bottom lid 21 of the toilet bowl isoperatively coupled to the switch button 71 so as to open temporarilywhen the button 71 is depressed.

A plurality of the toilet booths 101 of either of the first and secondembodiments may be coupled together. In this case, the number of thesewage tanks 24 used with these toilet booths 101 may be smaller thanthe number of these toilet booths 101, which each include one toiletbowl 18. If a plurality of the toilet booths 101 of the first embodimentare coupled together, since the sewage tank 24 of the second embodimenthas a larger capacity, the number ratio of the toilet booths 101 coupledtogether to the sewage tanks 24 used with these toilet booths may befrom about 1:1 to about 4:1. Also, the toilet booth 101 and the controlbooth 102 may be integrated into a single toilet unit. In any of thesearrangements, the entire structure is sufficiently compact in size,because the sewage tank or each of the tanks 24 serves the triplepurpose as conventional evaporation tank, microbial decomposition tankand storage tank.

The toilet unit of either of the embodiment may further include at leastone urinal. In this case, at least one toilet booth may include aplurality of urinals. The toilet bowls shown are of the Japanese style.But a western style toilet bowl may be used instead.

Flush water may be injected into the toilet bowl in a manner differentfrom the manner shown. If the toilet is what is known as a lightflushing type toilet, 400 to 500 cc of flush water is consumed per use.If a “Shatore” type (suction-and-pressurized-water-feed type) flushtoilet (which is high in cleaning power) is used, the water consumptionper use would be about twice that of a light flushing type toilet, andthus the throughput will be about twice.

The heater 43 may be provided, not in the sewage tank 24 as in theembodiments, but around the sewage tank 24 to heat the interior of thetank 24. Maintenance of the heater is easier with this arrangement. Butfrom the viewpoint of heat efficiency, it is preferable to provide theheater 43 in the sewage tank 24 and further provide the insulatingmaterial.

Water may be supplied from outside. For example, rainwater may usefulespecially if the temporary toilet according to the present invention isinstalled outdoors and can be connected to neither a sewage system nor awater supply system. FIG. 10 schematically shows a modification of thefirst embodiment which includes a rainwater supply mechanism. Forclarification, some elements that are not related to the supply ofrainwater are omitted in FIG. 10.

In this modified embodiment, an open-topped rainwater storage tank 106is provided on the rooftop of the toilet booth 101 of the toilet unit100. A rainwater discharge port 81 is formed in the bottom of the tank106. Rainwater collected in the tank 106 is fed downward through arainwater supply pipe 82. A rainwater regulating valve 83 is provided inthe rainwater supply pipe 82. Downstream of the valve 83, the pipe 82has a rainwater supply port 84 through which rainwater is supplied intothe flush water tank 11. A flush water level sensing float 85 isprovided in the flush water tank 11. The control unit 51 determineswhether the level of the flush water in the tank 11 is higher than anupper limit and lower than a lower limit, and throttles and opens therainwater regulating valve 83 if the water level is higher than theupper limit and lower than the lower limit, respectively.

However, when such rainwater is supplied or if flush water is suppliedinto the flush water tank from outside in order to make up for temporaryoveruse of flush water, the total amount of water present in the variouslocations of the entire toilet unit 100 increases. The control unit 51determines such total amount based on the positions of the floatingwater level sensor 61 and the flush water level sensing float 85, and ifthe control unit 51 determines that the total water amount is excessive,the control unit 51 reduces the amount of water supplied back into theflush water tank 11 through the water vapor separator 33, whiletemporarily increasing the amount of water discharged to outside.

EXAMPLES

Description is made of the specific amounts of water used in the variouslocations of each of the first and second embodiments. First regardingthe first embodiment, 500 cc of water was flushed per use. The watercontent in the sewage tank 24 was 400 liters. The toilet was used about60 times over a period of one week. 40 liters of waste was introducedinto the sewage tank 24 per day on the average, and 30 liters of waterwas returned to the flush water tank 11 as flush water, whose capacitywas 40 liters, per day on the average. 75% of the sewage introduced intothe sewage tank 24 was recovered as flush water. During the one-weekperiod, the total amount of water stored in various locations of theentire toilet unit 100 changed little.

Now regarding the second embodiment, 500 cc of water was flushed per useas in the first embodiment. The water content in the sewage tank 24 was600 liters. The sewage tank 24 was used for two of the toilet booths 101over a period of one week. 300 liters of water was returned to the flushwater tank 11 per day. During the one-week period, the total amount ofwater stored in the various locations of the entire toilet unit 100remained substantially unchanged.

DESCRIPTION OF THE NUMERALS

-   11. Flush water tank-   12. Foot pump chamber-   13. Foot pump-   14. Foot pedal switch-   15. Pump suction pipe-   16. Pump feed pipe-   17. Nozzle-   18. Toilet bowl-   21. Lid-   22. Waste storage tank-   23. Sewage discharge pipe-   24. Sewage tank-   31. Air exhaust pipe-   32. Air pressurizing pump-   33. Water vapor separator-   34. Water supply pipe-   35. Discharge tube-   36. Exhaust fan-   41. Blower pump-   42. Blower diffuser tube-   43. Heater-   44. Heat insulating material-   51. Control unit-   52. Temperature regulator-   53. Temperature sensor-   61. Floating water level sensor-   62. Use prohibition display-   63. Air intake port-   64. Overflow drain-   71. Switch button-   72. Water suction pump-   73. Waste feed pump-   74. Center hole-   75. Compressor-   81. Rainwater discharge port-   82. Rainwater supply pipe-   83. Rainwater regulating valve-   84. Rainwater supply port-   85. Flush water level sensing float-   100. Toilet unit-   101. Toilet booth-   102. Control booth-   103. Base-   104, 104′. Toilet bowl body-   105. Door-   106. Rainwater storage tank-   A. Sewage-   B. Sewage-   C. Water vapor-   D. Flush water-   E. Dry exhaust air

1. A temporary toilet comprising a toilet bowl, a flush water toiletwhich keeps flush water to be supplied into the toilet bowl, a sewagetank which keeps sewage discharged from the toilet bowl, a water vaporseparator capable of separating water from a gas containing a watervapor which has been evaporated in the sewage tank, an exhaust pipethrough which a gas is guided from a top of the sewage tank to the watervapor separator, and a water supply pipe through which water separatedin the water vapor separator is supplied into the flush water tank,wherein storage of sewage, microbial decomposition of waste, andevaporation of sewage take place in the sewage tank only.
 2. Thetemporary toilet of claim 1, further comprising a blower diffuser tubeprovided in the sewage tank and capable of discharging a gas whichagitates sewage in the sewage tank.
 3. The temporary toilet of claim 1,further comprising a heater provided in the sewage tank and capable ofheating sewage in the sewage tank.
 4. The temporary toilet of claim 3,wherein the heater is capable of heating the sewage in the sewage tankto a temperature of 25° or higher and 30° C. or lower, and wherein thetemporary toilet further comprises a control unit configured todeactivate the heater when the temperature of the sewage reaches apredetermined upper limit.
 5. The temporary toilet of claim 1, furthercomprising a floating water level sensor provided in the sewage tank soas to be movable in the sewage tank as the level of sewage in the sewagetank, a switch connected to the floating water level sensor, wherein thefloating water level sensor and the switch are configured such that theswitch is opened or closed when the level of the sewage in the sewagetank rises to a predetermined level, and a use prohibition displayprovided outside of the toilet and configured such that the indicationon the display changes to indicate that the toilet cannot be used whenthe switch is opened or closed.
 6. The temporary toilet of claim 1,further comprising a solar cell panel and a battery for storingelectricity generated by the solar cell panel, wherein the electricitygenerated by the solar cell panel constitutes a total electricityconsumed by the toilet.
 7. The temporary toilet of claim 2, furthercomprising a heater provided in the sewage tank and capable of heatingsewage in the sewage tank.
 8. The temporary toilet of claim 2, furthercomprising a floating water level sensor provided in the sewage tank soas to be movable in the sewage tank as the level of sewage in the sewagetank, a switch connected to the floating water level sensor, wherein thefloating water level sensor and the switch are configured such that theswitch is opened or closed when the level of the sewage in the sewagetank rises to a predetermined level, and a use prohibition displayprovided outside of the toilet and configured such that the indicationon the display changes to indicate that the toilet cannot be used whenthe switch is opened or closed.
 9. The temporary toilet of claim 3,further comprising a floating water level sensor provided in the sewagetank so as to be movable in the sewage tank as the level of sewage inthe sewage tank, a switch connected to the floating water level sensor,wherein the floating water level sensor and the switch are configuredsuch that the switch is opened or closed when the level of the sewage inthe sewage tank rises to a predetermined level, and a use prohibitiondisplay provided outside of the toilet and configured such that theindication on the display changes to indicate that the toilet cannot beused when the switch is opened or closed.
 10. The temporary toilet ofclaim 4, further comprising a floating water level sensor provided inthe sewage tank so as to be movable in the sewage tank as the level ofsewage in the sewage tank, a switch connected to the floating waterlevel sensor, wherein the floating water level sensor and the switch areconfigured such that the switch is opened or closed when the level ofthe sewage in the sewage tank rises to a predetermined level, and a useprohibition display provided outside of the toilet and configured suchthat the indication on the display changes to indicate that the toiletcannot be used when the switch is opened or closed.
 11. The temporarytoilet of claim 2, further comprising a solar cell panel and a batteryfor storing electricity generated by the solar cell panel, wherein theelectricity generated by the solar cell panel constitutes a totalelectricity consumed by the toilet.
 12. The temporary toilet of claim 3,further comprising a solar cell panel and a battery for storingelectricity generated by the solar cell panel, wherein the electricitygenerated by the solar cell panel constitutes a total electricityconsumed by the toilet.
 13. The temporary toilet of claim 4, furthercomprising a solar cell panel and a battery for storing electricitygenerated by the solar cell panel, wherein the electricity generated bythe solar cell panel constitutes a total electricity consumed by thetoilet.
 14. The temporary toilet of claim 5, further comprising a solarcell panel and a battery for storing electricity generated by the solarcell panel, wherein the electricity generated by the solar cell panelconstitutes a total electricity consumed by the toilet.